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Morphology and internal texture of polymetallic nodules: a. spheroidal, botryoidal morphology, rough surface (3609-1-1); b. part of big nodule with irregular shape with complex morphology and more sediment material inside (3607); c. cross section of part of big nodule probably with older nodule as nucleus (3600); d. cross section of small nodule with nucleus of sediment material and concentric microlayers (3609-1-2).
Source publication
The geochemical characteristics of the polymetallic nodules from the Interoceanmetal exploration area in the eastern part of the Clarion-Clipperton Fractures Zone (CCZ), NE Pacific are studied. The nodules are enriched in Mn and reveal an Mn/Fe ratio of 2.74-6.06, which classify them mostly as mixed hydrogenetic-diagenetic type. They are also enric...
Context in source publication
Context 1
... nodules are between 1 and 10 cm in diameter (Fig. 2). The smaller nodules (<3 cm) have spheroidal or discoidal morphology. The larger nodules (>3 cm) usually have an asymmetrical shape with complex, mainly botryoidal-ellipsoidal-polynucleate morphology. The surface texture of the nodules is smooth or granular. Pores are filled with sediment material, cracks, radiolarian tests, and traces ...
Citations
... Their main mineral phases are finegrained, amorphous or poorly crystalline (10°Å manganate (todorokite), quartz, muscovite, vernadite). Detrital and authigenic minerals are chlorite, apatite, barite (Hikov et al., 2022a). The nodules are classified as diagenetic and hydrogenetic. ...
... Two nodules and one sediment sample were selected for the leaching procedure. (Hikov et al., 2022a). The sediment sample (3600/3-5) is from depth interval 3 to 5 cm and contains 0.70 wt % Mn, 4.36 wt % Fe and 211.15 ppm ƩREE (Hikov et al., 2022b). ...
The distribution of main elements and REE in sequential leached phases from deep-sea polymetallic nodules and sediments from the eastern part of the Clarion-Clipperton fractures zone, NE Pacific are studied. Results show extraction of Mn in the leach 2 in both nodules and sediments. The extraction of Fe, P and REE is different for leach 2, 3 and residual fraction for nodules and sediments. Phosphorous and REE have strong positive correlation which suggests that the phosphate component is the main important carrier of REE in both nodules and sediments but Fe-Mn oxyhydroxides and clay minerals cannot be excluded as carriers of REE.
... Such promising raw material are modern deep-sea polymetallic nodules which are rich of such strategic and critical metals as Cu, Ni, Co, Pb, Zn, Li, V, Mo, W, Pt, REE [8]. In addition to the study of deep-sea polymetallic nodules from the Interoceanmetal exploration area in the Clarion-Clipperton Fractures Zone, NE Pacific [9] we focus our study on ancient nodules and sediments with similar lithology and/or formed in similar paleogeodinamic environments from different stratigraphic levels from Bulgarian 25 w w w . s g e m . ...
... On the other hand negatively charged complexes of V, Pb, U and REE are attracted by the slightly positively charged FeOOH [8]. Two main types of nodule formation were destinguishedhydrogenetic and diagenetic precipitation, but often a mixed hydrogenetic-diagenetic type of precipitation was suggested [8,9]. ...
... REE enrichment probably occurred during and/or after the deposition of Mn phases and is due to adsorption processes of REEs from seawater onto the manganese-rich surfaces [7]. Most of the REE patterns of manganese minerals have positive cerium anomaly which corresponds to a hydrogenetic precipitation of deep-see nodules [9]. The negative Ce anomaly of the REE patterns of pyrolusite can be interpreted as diagenetic type of precipitation but pyrolusite has low REE content and most probably it is result of hydrothermal w w w . ...
The increased demand for raw materials requires to reassess some deposits that were not of economic interest in the past. Complex of modern geochemical and mineralogical methods (SEM-EDS, LA-ICP-MS, QUEMSCAN) are used to study the ore mineralization in the small scale Pozharevo manganese deposit, Western Srednogorie Zone, Bulgaria. The deposit is formed in the contact zone between Late Cretaceous andesite pyroclastic rocks and overlying volcanogenic-sedimentary rocks. Manganese mineralization forms colloform textures of alternating compositions from manganeserich phases (birnessite, hollandite, pyrolusite etc.), mixed silicon-manganese phases to silicon-rich phases and often brecciates volcanic clasts. In situ LA-ICP-MS study of trace elements shows significant amounts of Cu, Li, As, Sr, Mo, Ba, W, Tl, REE, some of them defined as critical raw materials. QUEMSCAN study demonstrates join deposition of Mn, K and Ba with volcanogenic-sedimentary origin while later pyrolusite probably is hydrothermal. Mineralogical and geochemical characteristics show hydrothermal-sedimentary origin of Mn mineralization but also it has common features with modern deep-sea polymetallic nodules and proposes similar paleogeodinamic environments. Our study shows that the Pozharevo manganese deposit has good potential for prospecting of critical elements.
